A vehicle-to-vehicle communication system has been proposed recently, in which any one of multiple vehicles transmits vehicle information, such as a traveling speed, a present location, and a traveling direction, of an own vehicle to different vehicles and successively receives vehicle information transmitted from the different vehicles. As a device used in such a vehicle-to-vehicle communication system, a vehicle-mounted device assists a driver for a driving operation according to the vehicle information of the different vehicles acquired through a vehicle-to-vehicle communication and the vehicle information of the own vehicle.
For example, Patent Literature 1 discloses a technique of determining whether an own vehicle and any different vehicle are likely to have an accidental contact according to the vehicle information of the vehicle in question and the vehicle information of the own vehicle and warning a driver to avoid an accidental contact when a likelihood of such an accidental contact is determined.
According to the disclosed technique, the driver can recognize presence of a vehicle traveling in a crossing direction when the driver is nearing an intersection with poor visibility.